Drug Interactions between Acid Reducer Plus Antacid and bismuth subcitrate potassium / metronidazole / tetracycline

Tetracycline and calcium carbonate should not be taken orally at the same time. Products that contain magnesium, aluminum, calcium, iron, and/or other minerals may interfere with the absorption of tetracycline into the bloodstream and reduce its effectiveness. If possible, it may be best to avoid taking calcium carbonate while your are being treated with tetracycline. Otherwise, you should separate dosing by 2 to 4 hours, tetracycline should be taken at least 2 hours before and not less than 6 hours after Suprep Bowel Prep (magnesium/potassium/sodium sulfates), or tetracycline and calcium carbonate should be taken as directed by your healthcare provider. Talk to your healthcare provider if you are unsure whether your medications contain something that could potentially interact or if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Tetracycline and magnesium hydroxide should not be taken orally at the same time. Products that contain magnesium, aluminum, calcium, iron, and/or other minerals may interfere with the absorption of tetracycline into the bloodstream and reduce its effectiveness. If possible, it may be best to avoid taking magnesium hydroxide while your are being treated with tetracycline. Otherwise, you should separate dosing by 2 to 4 hours, tetracycline should be taken at least 2 hours before and not less than 6 hours after Suprep Bowel Prep (magnesium/potassium/sodium sulfates), or tetracycline and magnesium hydroxide should be taken as directed by your healthcare provider. Talk to your healthcare provider if you are unsure whether your medications contain something that could potentially interact or if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Using bismuth subcitrate potassium together with tetracycline may decrease the effects of tetracycline. Administration of tetracycline and bismuth subcitrate potassium should be separated by two to three hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Using metroNIDAZOLE together with famotidine can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with proton pump inhibitors or H2-receptor antagonists may significantly increase the gastrointestinal absorption of bismuth from bismuth subcitrate potassium (also known as colloidal bismuth subcitrate or tripotassium dicitratobismuthate), a process that appears to be dependent on intragastric pH. In a study conducted in six healthy volunteers, administration of omeprazole 40 mg/day orally for 1 week increased mean bismuth peak plasma concentration (Cmax) and systemic exposure (AUC) from a single 240 mg dose of bismuth subcitrate potassium by 136% and 274%, respectively, compared to placebo. The magnitude of these changes correlated with the degree of hypochlorhydria. The study also reported that plasma levels of bismuth were sometimes briefly over the "toxic" threshold of 100 mcg/L, although the clinical relevance of this observation following more prolonged dosing is uncertain. In another study conducted in 12 healthy volunteers, ranitidine 300 mg given orally for two doses 9 hours apart increased the median bismuth Cmax and 8-hour AUC from a single 240 mg dose of bismuth subcitrate potassium by 95% and 141%, respectively, compared to placebo. These increases were not caused by changes in renal bismuth clearance. By contrast, pretreatment with ranitidine had no significant effects on plasma bismuth exposures from single doses of bismuth subsalicylate and bismuth subnitrate, with very little systemic absorption of bismuth either with or without ranitidine pretreatment despite both formulations containing considerable amounts of bismuth. Previous studies have also reported on the limited systemic absorption of bismuth from these salts. When Pylera (a treatment preparation for Helicobacter pylori infection that contains bismuth subcitrate potassium 420 mg, metronidazole 375 mg, and tetracycline 375 mg per recommended dose) was administered four times daily with omeprazole 20 mg orally twice daily for 6 days in 34 healthy volunteers, mean bismuth Cmax and AUC increased by 215% and 191%, respectively, compared to administration without omeprazole. Concentration-dependent neurotoxicity has been associated with long-term use of bismuth; however, it is unlikely to occur with short-term administration or steady-state blood concentrations below 50 ng/mL. In the study, one subject transiently achieved a bismuth Cmax higher than 50 ng/mL (73 ng/mL) following multiple dosing of Pylera with omeprazole but did not exhibit symptoms of neurotoxicity. According to the manufacturer, there is no clinical evidence to suggest that short-term exposure to bismuth Cmax concentrations above 50 ng/mL is associated with neurotoxicity.

MANAGEMENT: Caution is advised when bismuth subcitrate potassium is used concomitantly with proton pump inhibitors or H2-receptor antagonists. Since food is known to impair the gastrointestinal absorption of bismuth, some authorities recommend taking this combination with food to minimize the potential risk of bismuth toxicity. Additionally, the increased gastric retention time of bismuth in the presence of food may be clinically beneficial, as it likely prolongs the exposure of Helicobacter pylori to high concentrations of bismuth.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.